The authors report a rare case of cryptogenic osteomyelitis of the skull with an intracerebral and a subgaleal abscess. Total excision of the abscess extending from the cortical surface to the lateral ventricle led to ventriculitis and subgaleal cerebrospinal fluid collection. These complications could have been avoided by aspirating the abscess after removing the infected portion of the skull and the epidural granulation tissue. Neurosurgeons prefering to excise such an abscess should leave a small area of capsule at the base in order to avoid having to open the ventricle.